Images never show --> TypeError: Can not read property prototype

[Ghassan]

When running the examples in iruby. Plot.show in the browser generates the following:

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Javascript error adding output!
TypeError: Cannot read property 'pane' of undefined
See your browser Javascript console for more details.
Out[3]:
["display_data", "<IDS|MSG>", "2921bf49eb70d9bd96b21c38215b195320e4956f4f9497a9bde353574446c444", "{"msg_type":"display_data","msg_id":"d804d835-4cdd-4601-a427-82cfbaff7477","username":"kernel","session":"51465e7f-83a7-46d4-ab54-cf115441e807","version":"5.0"}", "{"username":"username","version":"5.0","msg_id":"8F7E63E9D1A84CEE8B01C38B8F38E97B","msg_t ...
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instead of displaying the plot. I also noticed on the terminal the following messages when I start iruby notebook at the examples folder:

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/usr/local/lib/ruby/gems/2.2.0/gems/nyaplot-0.1.6/examples/notebook $ iruby notebook
Could not load bundler: iruby is missing from Gemfile. This might not work.
Add gem 'iruby' to your Gemfile to fix it.
[I 14:18:02.945 NotebookApp] Serving notebooks from local directory: /usr/local/lib/ruby/gems/2.2.0/gems/nyaplot-0.1.6/examples/notebook
[I 14:18:02.945 NotebookApp] 0 active kernels
[I 14:18:02.945 NotebookApp] The IPython Notebook is running at: http://localhost:8888/
[I 14:18:02.945 NotebookApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
[W 14:18:13.391 NotebookApp] Notebook 3DPlot.ipynb is not trusted
[I 14:18:13.746 NotebookApp] Kernel started: c2a15589-00b2-45a9-a7bc-7400cbcaa81a
W, [2016-02-16T14:18:14.585399 #4832] WARN -- : Could not load bundler: iruby is missing from Gemfile. This might not work.
Add gem 'iruby' to your Gemfile to fix it.
/usr/local/lib/ruby/gems/2.2.0/gems/iruby-0.2.8/lib/iruby/command.rb:108:in check_bundler' /usr/local/lib/ruby/gems/2.2.0/gems/iruby-0.2.8/lib/iruby/command.rb:67:inrun_kernel'
/usr/local/lib/ruby/gems/2.2.0/gems/iruby-0.2.8/lib/iruby/command.rb:34:in run' /usr/local/lib/ruby/gems/2.2.0/gems/iruby-0.2.8/bin/iruby:5:in<top (required)>'
/usr/local/bin/iruby:22:in load' /usr/local/bin/iruby:22:in

'
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hope this helps.

P.S. note that arrows above are added by me for clarity. Thank you.